1. Field of the Invention
The present invention relates to a steering wheel in which a decorative member made of a synthetic resin is mounted and fixed to a steering main body, and in particular, to a steering wheel which is superior in mounting property of a decorative member, and which is capable of appropriately deforming when the steering wheel is subjected to a load.
2. Description of the Related Art
In general, a steering wheel of an automobile has a steering main body which is constructed in such a manner that a boss portion and a circular ring-shaped rim portion to be coupled to a sheering shaft are coupled by way of a plurality of spoke portions. In addition, an air bag device is attached to the boss portion of the steering main body, and a pad portion having a horn mechanism is mounted so as to cover the airbag device.
Further, at the periphery of the pad portion, a decorative member (which may also be referred to as a garnish or an ornament) is mounted so as to cover the spoke portions of the steering main body, and a design property of the steering wheel is enhanced by this decorative member. Moreover, a stepped difference between the rim portion and the pad portion of the steering main body is reduced, whereby operability or operational stability of the steering wheel may also be improved.
An example of the steering wheel to which such a decorative member has been mounted is described in Japanese Unexamined Patent Application Publication No. 2012-144076, for example.
The steering wheel described in Japanese Unexamined Patent Application Publication No. 2012-144076 is constructed in such a manner that a decorative member (an ornament) is mounted to a steering main body. The steering main body is provided with: a circular ring-shaped rim portion; a boss portion (a hub portion) which is arranged at a center part of the rim portion; a plurality of spoke portions configured to couple the rim portion and the boss portion to each other.
Also, the decorative member has: one pair of left and right first and second decorative members; and a third decorative member which is assembled and fixed between the first and second decorative members. In addition, the first to third decorative members are respectively formed by way of insertion molding of a synthetic resin, and the left and right side edge parts of the third decorative member are slidably inserted into, and are engaged with, an opposite side edge part of the first decorative member and an opposite side edge part of the second decorative member, whereby an assembled decorative member in which the first decorative member to the third decorative member have been integrally assembled with each other is constructed.
In particular, in so far as the assembled decorative member in Japanese Unexamined Patent Application Publication No. 2012-144076 is concerned, an opposite end face which forms a gap between the first decorative member and third decorative member and an opposite end face which forms a gap between the second decorative member and the third decorative member are constructed so as to be inclined faces, both of which are obliquely disposed so as to cross each other with respect to the line of sight of a driver who faces a front side with respect to the steering wheel.
Such an assembled decorative member in Japanese Unexamined Patent Application Publication No. 2012-144076, in its entire shape, forms a substantial Y-shape in a planar view, and is mounted and fixed to the steering main body so as to follow an outer circumferential part of the pad portion in the steering wheel.
In this case, on a back face of the assembled decorative member, a plurality of lattice-shaped reinforcement ribs and a mounting and fixing portion which are coupled to the reinforcement ribs are integrally formed with the assembled decorative member; the assembled decorative member is positioned by way of an engaging lock pin or the like with respect to the spoke portions of the steering main body; and by way of screw tightening, the mounting and fixing portion that is provided on the back face of the assembled decorative member is secured and fixed to a mounting base which is formed at the spoke portions.
In so far as the assembled decorative member in Japanese Unexamined Patent Application Publication No. 2012-144076 is concerned, securing and fixing exerted by screw tightening is utilized, as described previously, as a unit configured to fix the decorative member (the assembled decorative member) to the steering wheel. In this way, in the conventional steering wheel, in order to fix the steering main body and the decorative member to each other, in general, the decorative member is fixed to the steering main body by employing fixing parts such as screws, machine screws, or bolts.
However, in a case where the decorative member is thus fixed to the steering main body by employing the fixing parts such as screws or machine screws, the number of parts increases, and therefore, there has been a case in which management of parts becomes complicated, or alternatively, there has been a case in which the assembling process of the steering wheel becomes complicated.
In addition, in a case where the decorative member is fixed by employing the fixing parts such as screws or machine screws, there is a need to provide a mounting and fixing portion for mounting the fixing parts on the decorative member, and however, there has been a case in which a setup position of the mounting and fixing portion is limited in consideration of the assembling work or the like of the steering wheel. Further, in a case where the decorative member is designed so as to be formed in an elongated shape, for example, there has been a case in which it becomes difficult to provide the mounting and fixing portion on the decorative member, or alternatively, there has been a case in which it becomes difficult to carry out the assembling work.
In a case where the fixing parts such as screws or machine screws are thus employed, the degree of freedom in design of the steering wheel is often lowered, and therefore, it is desired to employ a unit configured to fix the decorative member to the steering main body without a need to employ the fixing parts.
On the other hand, the steering wheel is constructed so as to absorb and mitigate an impact which is applied to a driver or the like, by deforming the steering wheel when the steering wheel is subjected to an input of a load exerted by a driver or the like from a driver's seat, for example, at the time of collision of an automobile or the like.
Thus, it is desirable that the steering wheel be constructed so that the amount of deformation of the steering wheel (in particular, the amount of deformation of the steering main body) is as large as possible in order to enhance the relevant impact absorption performance, and however, in a case where the decorative member is fixed to the steering main body by employing the fixing parts such as screws or machine screws, as described previously, deformation of the steering main body is restrained by the decorative member, depending on the setup position of the mounting and fixing portion in the decorative member or the mounting portion of the fixing parts.
Thus, in the conventional art, even if the decorative member is fixed to the steering main body by employing the fixing parts, a design of the decorative member is made in such a manner that deformation of the steering main body is restrained, thus resulting in a further lowering of the degree of freedom in design of the steering wheel, and for example, there has been a case in which it becomes difficult to design the decorative member so as to be formed in a narrow elongated shape, or alternatively, there has been a case in which it becomes difficult to make a difference in external view of the steering wheel or to enhance its related design property.
On the other hand, if an attempt is made to form an elongated design portion as a decorative member by way of painting, for example, there is a need to provide masking or the like for the sake of painting, or alternatively, it takes long for such painting to dry, thus resulting in higher costs, and in the case of such painting, it is difficult to produce a sharp sense of feeling in external view.